Comment 256 for bug 124406

Rolf,

We all know it's not specific to ubuntu, there's plenty of comments and links in this long thread pointing to the same issue on other distro. However this thread is probably the most active in discussing this issue. I guess that's the price for success ;) and the fact that there are a lot of people having this issue.

Regarding usb speed theory, maybe it's an issue between low and full speed usb (both handled by usb 1.1 while high speed is usb 2.0). So perhaps it would be interesting to test on your x24 various combination of low and full speed usb devices. Bear in mind however that once this bug happens, it seems to be "sticky" meaning there are times it happens even after the mouse/keyboard have been disconnected. So it's best to try each config after a cold boot.

See http://www.mjmwired.net/kernel/Documentation/usb/ehci.txt for info on usb in linux kernel. Interesting part:
Note that USB 2.0 support involves more than just EHCI. It requires other changes to the Linux-USB core APIs, including the hub driver, but those changes haven't needed to really change the basic "usbcore" APIs exposed to USB device drivers.

So it could be that this bug has been introduced since the addition of ehci, and is affecting usb1.1 as a result of the changes made to accomodate ehci.